Bile acid quantification of 20 plasma metabolites identifies lithocholic acid as a putative biomarker in Alzheimer’s disease

Introduction

There is still a clear need for a widely available, inexpensive and reliable method to diagnose Alzheimer’s disease (AD) and monitor disease progression. Liquid chromatography–mass spectrometry (LC-MS) is a powerful analytic technique with a very high sensitivity and specificity.

Objectives

The aim of the present study is to measure concentrations of 20 bile acids using the novel Kit from Biocrates Life Sciences based on LC-MS technique.

Methods

Twenty bile acid metabolites were quantitatively measured in plasma of 30 cognitively healthy subjects, 20 patients with mild cognitive impairment (MCI) and 30 patients suffering from AD.

Results

Levels of lithocholic acid were significantly enhanced in plasma of AD patients (50?±?6 nM, p?=?0.004) compared to healthy controls (32?±?3 nM). Lithocholic acid plasma levels of MCI patients (41?±?4 nM) were not significantly different from healthy subjects or AD patients. Levels of glycochenodeoxycholic acid, glycodeoxycholic acid and glycolithocholic acid were significantly higher in AD patients compared to MCI patients (p?<?0.05). All other cholic acid metabolites were not significantly different between healthy subjects, MCI patients and AD patients. ROC analysis shows an overall accuracy of about 66%. Discriminant analysis was used to classify patients and we found that 15/23 were correctly diagnosed. We further showed that LCA levels increased by about 3.2 fold when healthy subjects converted to AD patients within a 8–9 year follow up period. Pathway analysis linked these changes to a putative toxic cholesterol pathway.

Conclusion

In conclusion, 4 bile acids may be useful to diagnose AD in plasma samples despite limitations in diagnostic accuracy.

     

Polymer coated liposomes for use in the oral cavity – a study of the in vitro toxicity,effect on cell permeability and interaction with mucin

In this study we investigated the in vitro toxicity, impact on cell permeability and mucoadhesive potential of polymer-coated liposomes intended for use in the oral cavity. A TR146 cell line was used as a model. The overall aim was to end up with a selection of safe polymer coated liposomes with promising mucoadhesive properties for drug delivery to the oral cavity. The following polymers were tested: chitosan, low-methoxylated pectin (LM-pectin), high-methoxylated pectin (HM-pectin), amidated pectin (AM-pectin), Eudragit, poly(N-isopropylacrylamide-co-methacrylic acid) (p(NIPAAM-co-MAA)), hydrophobically modified hydroxyethyl cellulose (HM-HEC), and hydrophobically modified ethyl hydroxyethyl cellulose (HM-EHEC). With chitosan as an exception, all the systems exhibited no significant effect on cell viability and permeability at the considered concentrations. Additionally, all the formulations showed to a varying degree an interaction with mucin (BSM type I-S); the positively charged formulations exhibited the strongest interaction, while the negatively and neutrally charged formulations displayed a moderate or low interaction. The ability to interact with mucin makes all the liposomal formulations promising for oromucosal administration. Although the chitosan-coated liposomes affected the cell viability, this formulation also influenced the cell permeability, which makes it an interesting candidate for systemic drug delivery from the oral cavity.     

Outcomes of endoscopic ultrasound‐guided pancreatic FNAC diagnosis for solid and cystic lesions at Manchester Royal Infirmary based upon the Papanicolaou Society of Cytopathology pancreaticobiliary terminology classification scheme

Objective

To compare endoscopic ultrasound (EUS)‐FNAC diagnosis of pancreatic lesions with patient outcome based upon the Papanicolaou Society of Cytopathology pancreaticobiliary terminology classification scheme diagnostic categories: Panc 1 (non‐diagnostic); Panc 2 (negative for malignancy/neoplasia); Panc 3 (atypical); Panc 4B (neoplastic, benign); Panc 4O (neoplastic, other); Panc 5 (suspicious of malignancy); and Panc 6 (positive/malignant).

Methods

All EUS‐FNA pancreas specimens taken at Manchester Royal Infirmary in 2015 were prospectively classified according to the above scheme at the time of cytology reporting and data recorded prospectively. Subsequently, outcomes based on clinical follow‐up or histopathology diagnosis were compared with the cytology diagnosis.

Results

120 EUS‐FNA pancreas specimens from 111 patients were received, of which 112 (93.3%) specimens had follow‐up data. There were 79 and 41 EUS‐FNA pancreas specimens from solid and cystic lesions, respectively. Based on the cytology diagnosis the specimens were classified as Panc 1 (7.5%), Panc 2 (33.3%), Panc 3 (2.5%), Panc 4B (2.5%), Panc 4O (15.0%), Panc 5 (3.3%) and Panc 6 (35.9%). The performance indicators for diagnosis of malignancy or neoplasia with malignant potential, included sensitivity (95.4%), specificity (100%), positive predictive value (100%), negative predictive value (92.3%), false positive rate (0%) and false negative rate (4.6%).

Conclusions

The Papanicolaou Society of Cytopathology pancreaticobiliary terminology classification scheme is a logical system that can easily be introduced in a diagnostic cytopathology service. This classification scheme acts as an aid to diagnostic reporting, clear communication of significant results including risk of neoplasia/malignancy to clinicians, clinical audit and comparison of results with other centres.     

Evidence for diet partitioning among three coexisting native freshwater fishes in South Africa's Cape Fold Ecoregion

The partitioning of limited resources commonly explains how different species can coexist within the same ecological community. In this 2010 study, the diets of three coexisting freshwater fishes (Cape galaxias Galaxias zebratus, n = 27; Cape kurper Sandelia capensis, n = 60; Breede River redfin Pseudobarbus burchelli, n = 77) were characterised and compared in three headwater streams in South Africa's Cape Fold Ecoregion using gut contents and stable isotope analyses. These data were analysed to ascertain whether the three species exploit distinct trophic niches. Both approaches provided evidence that these species occupy different trophic niches, though with some overlap. However, dietary differences among sites were not consistent and were probably influenced by site-specific factors like resource availability. Pseudobarbus burchelli had a broader niche breadth at Tierkloof Stream than the other two species, but not at Waaihoek or Tierstel Streams. Our results also suggest that P. burchelli consumed a more omnivorous diet than do the other two species, whereas S. capensis occupied a higher trophic position than the other two species and consumed vertebrates. Our findings suggest that these species occupy non-equivalent feeding niches in Cape Fold Ecoregion headwater streams, and that diet partitioning might facilitate their coexistence in these systems.     

Clinical utility of tumor genomic profiling in patients with high plasma circulating tumor DNA burden or metabolically active tumors

Background

This retrospective study was undertaken to determine if the plasma circulating tumor DNA (ctDNA) level and tumor biological features in patients with advanced solid tumors affected the detection of genomic alterations (GAs) by a plasma ctDNA assay.

Method

Cell-free DNA (cfDNA) extracted from frozen plasma (N?=?35) or fresh whole blood (N?=?90) samples were subjected to a 62-gene hybrid capture-based next-generation sequencing assay FoundationACT. Concordance was analyzed for 51 matched FoundationACT and FoundationOne (tissue) cases. The maximum somatic allele frequency (MSAF) was used to estimate the amount of tumor fraction of cfDNA in each sample. The detection of GAs was correlated with the amount of cfDNA, MSAF, total tumor anatomic burden (dimensional sum), and total tumor metabolic burden (SUVmax sum) of the largest ten tumor lesions on PET/CT scans.

Results

FoundationACT detected GAs in 69 of 81 (85%) cases with MSAF >?0. Forty-two of 51 (82%) cases had ≥?1 concordance GAs matched with FoundationOne, and 22 (52%) matched to the National Comprehensive Cancer Network (NCCN)-recommended molecular targets. FoundationACT also detected 8 unique molecular targets, which changed the therapy in 7 (88%) patients who did not have tumor rebiopsy or sufficient tumor DNA for genomic profiling assay. In all samples (N?=?81), GAs were detected in plasma cfDNA from cancer patients with high MSAF quantity (P?=?0.0006) or high tumor metabolic burden (P?=?0.0006) regardless of cfDNA quantity (P?=?0.2362).

Conclusion

This study supports the utility of using plasma-based genomic assays in cancer patients with high plasma MSAF level or high tumor metabolic burden.

     

Analysis of Neurotrophin/Receptor Interactions with a gD-Flag-Modified Quantitative Kinase Receptor Activation (gD.KIRA) Enzyme-Linked Immunosorbent Assay

A rapid, sensitive, and high-capacity assay has been developed to quantify ligand-induced receptor tyrosine kinase activation in terms of receptor phosphorylation. The assay, termed a “kinase receptor activation” or KIRA-ELISA, utilizes two separate microtiter plates, one for cell culture and ligand stimulation, and the other for receptor capture and phosphotyrosine ELISA. The assay was developed for analysis of neurotrophin-induced trkA, trkB, or trkC activation. It utilizes a trkA, trkB, or trkC receptor fused with a 26-amino-acid polypeptide flag derived from HSV glycoprotein D (gD.trkA, B, or C, respectively) on the amino-terminus, stably transfected into CHO cells. Stimulated receptors were solubilized with Triton X-100 buffer and then captured in ELISA wells coated with gD-specific mAb. The degree of receptor autophosphorylation was quantified by anti-phosphotyrosine ELISA. Reproducible standard curves were generated with an EC₅₀of approximately 16 ng/ml NGF for gD.trkA KIRA, 11 ng/ml for NT4/5 and 20 ng/ml for BDNF in gD.trkB KIRA, and 9.4 ng/ml for NT3 in gD.trkC KIRA. When the gD.trkA KIRA assay was used to quantify serum NGF or NT3 following administration to rats, the assay agreed well with currently existing ELISA assays. When the gD.trkA KIRA assay was used to test several NGF variants, as well as NGF stability samples, the capacity of the assay to quantify ligand bioactivity compared well with the more widely used radioreceptor binding and PC 12 cell survival assays. The gD.trk KIRA assays show great potential as rapid bioassays, capable of quantitative, consistent, and stability indicating analyses.